Nerwen, what you wrote about Asta and Coldan is exactly what I had in mind for them. Nice!
As you see, I'm letting you decide how Coldan is going to spend the time until the rehearsal starts, as he'll try to stay around Asta unless strongly rebuked - I hope that's OK. Whatever you do is fine with me, and if you find a way to get rid of him, well, the poor darling will just have to sublimate and maybe add a line or two to
The Fall of King Bladorthin.
(As far as 'explaining himself' to Asta goes, I doubt he will anytime soon - he's had lots of chances before...)